The Development of a Performance Assessment Framework for Geologic CO2 Sequestration

Large-scale implementation of geologic storage in the U.S. implies seals with a cumulative area amounting to hundreds of square kilometers per year and will require a large number of storage sites. These factors highlight the need for a robust and reliable method for evaluating the suitability of specific sites to ensure that they will perform to required goals. This method must address fundamental physics and chemistry over a large range in scale and must address uncertainties both in these phenomena and in the properties of the reservoir. In addition, the method must link these fundamental scientific inputs to decisions based on a required goal (e.g. <0.01% of CO2 released per year). The Zero Emissions Research and Technology (ZERT) project at the Los Alamos National Laboratory is studying the injection of CO2 into geologic repositories. We have developed a coupled process-system model that is intended to evaluate critical pathways for CO2 transport in the system and MMV challenges/strategies associated with those pathways. In order for the systems model to be valid it must be supported by process level models that address the fundamental physics and chemistry at the appropriate scale. This study discusses upscaling and abstraction methods that link the process level models to the systems model CO2-PENS. Our approach has been to identify the key processes in each of the subsystems in geologic storage (reservoir to surface). In developing the framework, we are focusing in several specific subsystems: wellbore integrity, fracture/fault integrity, saturated zone interactions, terrestrial ecosystems and atmospheric processes. This talk will focus on the general framework and the abstraction process for incorporating process level information into the systems model for each of these subsystems. A poster by Stauffer et al. describes the CO2-PENS systems model in greater detail.